Lu Shaoyu, Yan Li, Zhong Wen, Jing Chuanyong
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Langmuir. 2022 Jan 11;38(1):275-281. doi: 10.1021/acs.langmuir.1c02474. Epub 2021 Dec 22.
Hydration of TiO facets controls the reactions occurring at the mineral-water interfaces. However, the underlying mechanism of the facet-dependent hydration and the effect of hydration on contaminant adsorption are still ambiguous. Herein, arsenite [As(III)] adsorption on hydrated {001}, {100}, {101}, and {201} TiO was explored by integrating multiple characterizations and density functional theory (DFT) calculations. Our macroscopic adsorption results show an As(III) adsorption density order of {201} > {100} > {101} > {001}, though As(III) on each facet formed a bidentate binuclear structure, as evidenced by the extended X-ray absorption fine structure analysis. The diffuse reflectance infrared Fourier transform spectroscopy analysis identified distinctive surface hydroxyls on four-faceted TiO upon water adsorption. The hydrated surface regulated the subsequent As(III) adsorption, giving an As(III) adsorption energy order of {201} (-0.95 eV) < {100} (-0.38 eV) < {101} (-0.005 eV) < {001} (0.04 eV) according to DFT calculations. The As(III) adsorption energy on hydrated facets was linearly correlated with the macroscopical As(III) adsorption density ( = 0.99, < 0.05), revealing that the impregnable water binding highly suppressed the exchange of As(III) molecules with adsorbed water. Our study provided a novel insight into the facet-dependent interfacial adsorption.
TiO晶面的水合作用控制着矿物 - 水界面发生的反应。然而，晶面依赖性水合作用的潜在机制以及水合作用对污染物吸附的影响仍不明确。在此，通过整合多种表征方法和密度泛函理论（DFT）计算，研究了亚砷酸盐[As(III)]在水合的{001}、{100}、{101}和{201} TiO上的吸附情况。我们的宏观吸附结果表明，As(III)的吸附密度顺序为{201} > {100} > {101} > {001}，尽管通过扩展X射线吸收精细结构分析证明，每个晶面上的As(III)都形成了双齿双核结构。漫反射红外傅里叶变换光谱分析确定了水吸附后四面TiO上独特的表面羟基。水合表面调节了随后的As(III)吸附，根据DFT计算，As(III)的吸附能顺序为{201}（-0.95 eV）< {100}（-0.38 eV）< {101}（-0.005 eV）< {001}（0.04 eV）。水合晶面上的As(III)吸附能与宏观As(III)吸附密度呈线性相关（ = 0.99， < 0.05），这表明牢固的水结合极大地抑制了As(III)分子与吸附水的交换。我们的研究为晶面依赖性界面吸附提供了新的见解。
